Telegraphone.



No. 873,083. PATENTED DEC. 10, 1907.

V. POULSEN & P. PBDBRSEN.

TELEGRAPHONE.

APPLICATION FILED JUNE 12. 1902. BENEWED HAY 2, 1907.

@fuggi m @Ivi-P44053@ o NITED STATES 'PATENT OFFICE.

VALDEMAR POULSEN AND FEDER OLOF PEDERSEN, OF COPNHAGEN, DENMARK, ASSIGNORS TO AMERICAN TELEGRAPHONE COMPANY, A CORPORATION OF THE DISTRICT OF COLUMBIA.

Specification of Letters Patent.

Patented nec. 1o, 1907.

appuoauon mea .rm 12. looa. seran Na 111.305. Renewed my 2.1967. semi No. 371.454.

To all whom it may concern:

Beit known that we, VALDEMAR andlnnnn OLoF PEDERSEN, subjects of the King of Denmark in the Kingdom .oi n certain new and useful Improvements 41n Telegraphones, of which the following is .a

specification.

This invention relates to the telegraphone invented by V. Poulsen and described in U. S. Patent No. 661619 issued to him Nov. 13, 1900. The telegraphone comprises a' steel body'in which a magnetic recor of speech,

sounds, telegraphic signals or interru tions of alternating currents is made by ane ectromagnet Whose ypole or poles are Within magnetizing distance of said body While the latter is movingwith respect thereto, and While the electrical undulations created by said speeches are traversing said magnet. For obliterating the magnetic record thus produced, a continuous current is ordinary traversed the magnet, While the'portion of the steel body containing the record is again moved past the magnet. The constant magnetism of the magnet obliterates the magnetical record and leaves the steel body in ,a permanent uniform magnetic condition throughout. In order to make a new .record u on that portion of the steel body thus uni ornily magnetized, it is desirable to i '15" The polarizing battery-1s preferably put restore the steelbody to the most favorable condition to receive and preserve such record,

and this is done by usm what We call a polarizing batter inxcircuit `with the magnet and so connecte thatits influence `lwill nullify or partially nullify. the uniform-magnetic condition existing in the steel body and bring it back to anatural state, or nearly so, Whereitwill be most able to receive and preserve vthe magnetic record.

into circuit in such a manner that it accomplishes its purpose simultaneously with the makingfof the new record. In other Words, it is connected in the circuit leading fromthe secondary'winding of the transmitter induction coil, tothe recording magnet. By thus using the polarizin battery the sensitivenessof the steel bo y increases because the moleculesiare ut into a state of agitation'at,

` record decreases.

residing at' Copenhagen Denmark, have invented:

; l To illustrate the manner of carryingbut. PoULsnNl l the invention -the acompanymg dra apparatus connected u of the use offpermanent magnets.

Referring to Fig. 1, A represents the telegra hone, consisting of a horizontal cylinder a aving wound u on its surface the steel recording Wire b an adapted to be rotated by power applied gttthe pulley c or in any suit7 ment of the Wire b. T is a telephone transmitter, I its induction coil and R a telephone receiver. P is the polarizing batterym the secondary circuit of the induction coil. an obliterating battery and S is a switch .for connecting the various apparatuses with the telegraphone magnet e. The switch consists of two bars connected with the terminals contact with-different pairs of the terminals 1, 2, 3, 4 and 5. When the switch is on terminals 2 and 4 the transmitter and polarizing battery are connected with the telegra- `the receiver is connected with the' telegraphone-magnet and When on 8 and 5, as shown, 'the obliterating battery isl connected with the telegraphone magnet. `Hence when a record is being made, onthe steel body the transmitter is connected; when the record is `being reproduced, the receiver is connected and when the record is being obliterated, the battery O is connected.

It is not necessary to use separate vbatteries for polarizing and obliterating, as one and the same battery can be employed, provided suitable means are used for `varying the direction and strength of the current according to Whether the battery is used for obliterating or recording.

. Since the operations herein described are magnetic, it 1s obvious, that the obliterations of the record and the restoration of the magnetizable body rto a favorable condition can .be accomplished -with permanent magnets) .or'both permanent and lectro-,magnets less band and separate recording and reproducing magnets are used simultaneously, it

shows .in Figure 1, a diagram of circuits m proper manner-". -for the purpose; and 1n l ig. 2 an illustration Where the' steel body is in the form of an endable'manner.. e 1s the .telegraphone electromagnet Whose"` ole pieces Aengage the wirey b,"

so that it Will s ide along the rod d When/the cylinder turns by reason `of the spiral arrange-fA '70 Oisof the magnet and adapted to be moved into phone'magnet; When on terminals 1 and 3,

is convenient to use permanent magnets for obliterating the record and restoring the steel body to favorable condition. This plan is illustrated in Fig. 2, wherein b is an endless band or wire traveling in the direction of the arrow. The recording magnet is i tuted for one or more of the permanent magnets. v

What we claim and desire to secure by Letters Patent of the United States is:

1. In an apparatus for recording speech, sounds or current variations electro-ma netically, the combination of a magnetizab e body, a recordin magnet, a source of constant current an meanswhereby said current can be sent through the ma net successively in opposite directions an eventually with different strengths.

2. In an apparatus for recording speech, sounds or current variations electro-ma netically, the combination of a magnetizab e body, a recording magnet, means for uniformly magnetizing said body with opposite directions of the magnetic lines of force, substantially as described.

3. In an apparatus for recording speech, sounds, or current variations electro-ma netically, the combination of a magnetizab e body, a recording ma net, means for uniformly magnetizin sai body and means for further magnetically influencing said body to bring it to a magnetic condition most favor-4 able to receive and preserve a record, substantially as described.

4.'v InY an apparatus for recording speech,

sounds or current variations electro-magnetically the combination of a c ircuit transmittin apparatus in said circuits a batte in sai circuit, a magnetizable body, a recording electro-magnet, a second circuitconthrough the magnet in opposite directions,

substantially as describe 5. The method of operating telegraphones which consists in obliterating a magnetic record by uniformly magnetizing the body containing the record and theny uniformly remagnetizing said body with ma netic lines of force of opposite direction to ring'it to the most favorable condition to receive a new message, substantially as described.

6. The method of operating telegraphones which consists in obliterating a ma netic record by uniformly magnetizing the tainingthe record and then uniformly remagnetizin-g said body with an o posite direction `of the magnetic lines of orce, substantially as described.

7. TheA method of operating telegraphones, which consists in obliterating a ma netic record by uniformly magnetizing the 'ody containing the record and then simultaneously remagnetizing said body with auniformly magnetizing current, the magnetic lines of force of which have the o posite direction of the obliterating lines of orce, and a messa e current, substantially as described.

n testimony whereof we have hereunto set our hands in' the presence oftwo Witnesses.

VALDEMAR IOULSEN. PEDER OLOF PEDERSEN. i

Witnesses as to Poulsen: E. S. HAYEMANN, CARL SCHAU.

Witnesses as to Pedersen: WM. A.` ROSE'NBAUM, FRANK S. OBER.

ody con- 

